Closed-loop efficiency modulation for use in network powered applications

ABSTRACT

Methods for reducing power dissipation from an input power source in a telecommunications system are disclosed. In one embodiment the method includes: utilizing a first I2C device to monitor an input voltage and input current to a remote unit; providing the input voltage and input current to a main microprocessor for calculating an input power; utilizing a second I2C device to monitor an output voltage and output current from the remote unit; providing the output voltage and output current to the main microprocessor for calculating an output power; calculating a power efficiency of the remote unit at the main microprocessor based on the input power and the output power; utilizing a third I2C device to provide the power efficiency of the remote unit to a digital power manager; and utilizing the digital power manager to control the DA trim output to a DC/DC converter.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 12/454,135filed on May 13, 2009, to Simon P. Whittam, entitled “Closed-LoopEfficiency Modulation For Use in Network Powered Applications,”currently allowed; commonly assigned with the present invention andincorporated herein by reference.

FIELD OF DISCLOSURE

The disclosures made herein relate generally to the telecommunicationsindustry. The invention discussed herein is in the generalclassification of a method and a remote device such as a sealedexpansion module (SEM) for reducing power dissipation from an inputpower source.

BACKGROUND

Network powered applications (e.g. +/−190Vdc or +/−130Vdc applications)are subject to voltage drop losses on the twisted wire pair cables (e.g.22 AWG (American Wire Gauge)/24 AWG cables) that are typically used intelecommunications applications. The input power source is restricted tolevels defined by the RFT-V (Remote powering Feeding Telecom-Voltagelimited) specification. This restricts the input power source to maximumvoltage, current and power levels (i.e. +/−190V (volts)+/−3%; 265 mA(milliamperes); and 100VA (volt amperes or 100 watts), respectively)thus restricting the total available loop length for higher poweredapplications.

Bellcore GR-1089-CORE provides certain centralized coordinationstandards for the regional Bell operating companies and does not permitdirect paralleling of multiple power sources over respectivetelecommunication wires to supply power in excess of 100 VA. Moreover,paralleling of multiple twisted wire pair cables on a single loopincreases costs and reduces the number of available wires in a singlethree-hundred (300) wire bundle. Paralleling of multiple twisted wirepair cables onto a telecommunications wirewrap pin is also prohibited.In order to optimize the system efficiency using a limited input powersource and with traditional losses associated with a finite loopimpedance, any remote unit in the system must be as efficient aspossible in order to meet or exceed loop-length requirements from thepower source.

Currently, there is no existing solution to mitigate the voltage drop onthe twisted wire pair cables other than using more expensive, largergauge wire or multiple twisted wire pair cables. Therefore, aclosed-loop efficiency modulation technique within a remote device isneeded to optimize the power efficiency in the entire loop, therebyreducing the required input current and associated voltage drop from thepower source. This will allow the remote units/devices (e.g. SEMs) ofthe system to be placed farther from the input power source and willreduce the power dissipation inside the remote unit. In addition, thiswill increase reliability and reduce global hydro requirements.

Several technical terms will be used throughout this application andmerit a brief explanation. A sealed expansion module (SEM) is a sealedenclosure that can be mounted in a variety of locations and protects amyriad of electronics equipment. An SEM is often a compact, sealed,full-service Internet Protocol (IP) access node for remote deploymentsin a network and may offer multiple very high bit-rate digitalsubscriber line (VDSL) ports.

An integrated circuit (IC) is a miniaturized electronic circuit havingboth semiconductor devices and passive components. An IC is manufacturedin the surface of a thin substrate of semiconductor material and used invirtually any piece of electronic equipment.

An inter-integrated circuit (I2C) is a multi-master serial computer bus.It has a bi-directional two-wire design that utilizes a serial data line(SDL) and a serial clock line (SCL). The I2C bus is controlled by amaster device that tells various slave devices when they are permittedto access the bus. For example, a digital-to-analog converter (DAC)could be a slave device accessed via the master device.

A DAC is a device that converts a digital signal (e.g. a binary code) toan analog signal (e.g. current or voltage).

A DC to DC converter is an electronic circuit that converts a source ofdirect current from one voltage level to another. This is done becausemany electronic devices that are supplied with external power orinternal battery power contain multiple circuits that require differentvoltage levels than supplied by the external power source or internalbattery.

An opto-isolator is a device that uses a short optical transmission pathto transfer a signal between elements of a circuit (e.g. a transmitterand a receiver) while keeping them electrically isolated.

A bus or BUS is a common voltage rail used to power multiple nets/nodeswithin a power circuit. A communication protocol device is a computerbus. For example, but not by way of limitation, a communication protocoldevice may include a 1-Wire bus, HyperTransport bus, I2C bus, PCI(Peripheral Component Interconnect) Express bus, SPI (Serial PeripheralInterface) bus, or SMBUS (System Management bus).

SUMMARY OF THE DISCLOSURE

The present invention provides a method and remote device such as aremote sealed expansion module (SEM) for reducing power dissipation in atelecommunications loop.

In the preferred embodiment of this invention, a SEM contains a networkfeed monitor that receives an input voltage and current on a pair ofRing/Tip pairs. The input voltage is then transmitted to a DC/DCconverter and the voltage is adjusted and then transmitted to a BUS feedmonitor connected to an active load. A first I2C device is connected tothe network feed monitor to provide information related to input voltageand current to a main microprocessor that calculates input power. Asecond I2C device is connected to the BUS feed monitor and the activeload to provide information related to the output voltage and outputcurrent to the main microprocessor that calculates output power. Themain microprocessor is further connected through a third I2C device to adigital power manager that provides a DAC trim output to the DC/DCconverter for optimizing the efficiency of the system.

In an alternative embodiment, the first I2C device and the second I2Cdevice also transmit information related to temperature status inaddition to current and voltage readings.

The preferred method of this invention involves utilizing a first I2Cdevice to monitor an input voltage and input current to a remote unit;providing the input voltage and input current to a main microprocessorfor calculating an input power; utilizing a second I2C device to monitoran output voltage and output current from the remote unit; providing theoutput voltage and output current to the main microprocessor forcalculating an output power; calculating a power efficiency of theremote unit at the main microprocessor based on the input power and theoutput power; utilizing a third I2C device to provide the powerefficiency of the remote unit to a digital power manager; and utilizingthe digital power manager to control the DA trim output to a DC/DCconverter.

An alternative method of this invention involves utilizing the first I2Cdevice and the second I2C device to monitor temperature status inaddition to current and voltage status.

Under some applications, embodiments of the invention may provide amethod and remote device (e.g. a remote SEM) for reducing powerdissipation in a telecommunications loop.

Under some applications, embodiments of the invention may produce higherpower efficiency in a system utilizing an input power source and remotedevices that dissipate power connected on a loop.

Under some applications, embodiments of the invention may provide asystem that permits longer loop lengths in order to reach more customersdue to the ability to consume less power in each remote device connectedon the loop.

Under some applications, embodiments of the invention may provide anoverall system that will have increased efficiency and thereby draw lesspower from an input power source.

Under some applications, embodiments of the invention may provide a“green power solution” to meet new global standards by consuming lessenergy on shorter length loops.

Under some applications, embodiments of the invention may provide amethod that is relatively inexpensive to implement that reduces powerdissipation from an input power source in a telecommunications system.

Under some applications, embodiments of the invention may provide adevice that is relatively inexpensive to manufacture and deploy thatreduces power dissipation from an input power source in atelecommunications system.

Under some applications, embodiments of the invention may provide amethod and remote device that efficiently reduces power dissipation froman input power source in a telecommunications system.

Under some applications, embodiments of the invention may provide areliable method and remote device for reducing power dissipation from aninput power source in a telecommunications system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the preferred embodiment of the remote unit (SEM)utilizing an end-to-end efficiency modulation technique.

FIG. 2 depicts a method for providing end-to-end power efficiency in aremote unit (SEM).

FIG. 3 depicts an alternative method for providing end-to-end powerefficiency in a remote unit (SEM).

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the preferred embodiment of the remote unit (SEM)utilizing an end-to-end efficiency modulation technique. In thispreferred embodiment, a SEM 10 contains a network feed monitor 11 thatreceives an input voltage and current from an external power sourcealong a pair of Ring/Tip pairs. Other wire/cabling arrangements are alsopossible for voltage and current transmission. The input voltage is thentransmitted to a DC/DC converter 12 and the voltage is adjusted and thentransmitted to a BUS feed monitor 13 connected to an active load 14. Afirst I2C device 15 is connected to the network feed monitor 11 toprovide information related to input voltage and current to a mainmicroprocessor 16 that calculates input power. A second I2C device 17 isconnected to the BUS feed monitor 13 and the active load 14 to provideinformation related to the output voltage and output current to the mainmicroprocessor 16 that calculates output power.

The main microprocessor 16 calculates a power efficiency utilizing theinformation supplied related to the input power and output power. Themain microprocessor 16 is further connected through a third I2C device18 to a digital power manager 19 that provides a DAC trim output to theDC/DC converter 12 for optimizing the efficiency of the system. Voltagetrimming is a method of increasing the accuracy of a power supplythrough a correction signal that makes fine adjustments to the powersupply's output voltage. In this preferred embodiment, I2C optocouplerisolation for all I2C devices is required to meet safety isolationneeds.

The use of the preferred embodiment of the SEM 10 creates loop-lengthoptimization in network powered applications. Power supply efficiency atthe SEM 10 is a primary factor restricting the loop length availableusing a given input voltage source (e.g. 100VA (W) source) through theimpedances of and voltage drops associated with the telecommunicationcabling. The efficiency of an input power supply can be attributed toconduction and switching losses. Conduction losses are predominantlybased on current drawn through the switching devices and the series passelements (such as inductors and sense resistors). Switching losses arepredominantly based on switching device selection and voltage. Bydynamically modulating the variable output voltage of the main DC/DCconverter 11, these losses can be optimized by compromising one lossover the other. The overall efficiency range of the DC/DC converter 11can be tabulated and the peak efficiency state defined for eachoperating condition (variable line, load and temperature, etc).

The overall efficiency of the system is monitored by the mainmicroprocessor 16 and/or with the aid of a programmable logic devicesuch as a Field-Programmable Gate Array (FPGA). Communication throughI2C devices is discussed in conjunction with the preferred embodiment ofthe present invention; however, any other suitable communicationprotocol devices connected to the input device, the digital powermanager and the output monitoring devices would be appropriate for usewith the present invention. The input power and output power can becontinuously calculated as the digital power manager 19 trims, throughon-IC DAC, the output of the DC/DC converter 11 in order to optimize theoverall system efficiency. As line and load conditions change, thesystem can react rapidly given a fixed algorithm to find the bestefficiency setpoint for the new operating point.

For example, any time a condition changes related to line, load ortemperature, the first I2C device 15 and second I2C device 17communicate these changes in conditions to the main microprocessor 16. Apower efficiency of the SEM 10 is then calculated using the current andvoltage information provided from the input and the output under thesenew conditions. The power efficiency information is then sent to thedigital power manager 19 which sends a DAC trim output signal to theDC/DC converter 11, causing the DC/DC converter 11 to make adjustmentsto its output voltage. After the various DC/DC converter output voltagesare tested to determine the peak power efficiency for the SEM 10 underthe new operating conditions, the digital power manager 19 ensures thatthe DC/DC converter 11 operates with the appropriate output voltage toobtain the peak power efficiency under these conditions until anotherchange in conditions is detected.

By optimizing the efficiency, the system is capable of drawing lesspower from the input power source. In addition, the SEM 10 may be placedfarther from the input power source. This is a major benefit for remoteSEMS. It is estimated that efficiency modulation can establish a 3%-5%increase over the worst case efficiency specification of a fixed supply.This efficiency increase can create an increased loop length gain of10%. For a 5000 feet application, this creates an increase of 500 feetthus allowing more customers for a single fixed location SEM. For asystem dissipating 75VA (W) in a 100VA (W) limited application, theefficiency increase would only reduce the internal power dissipation bya few watts. If, however, thousands of these particular SEMs areinstalled, then the aggregate savings creates a substantial reduction inelectrical power needs for the customer and thus reduces the overallpower needs.

Remote users can port into the remote SEM and view real-time powerconsumption of the device. For example, a remote user could utilize asystem connection to the main microprocessor of the SEM.

The system software can also use the readings from the system to recordthe power usage history, indicate warnings of power threshold crossings,report errors or faults on the power feed and power draw, record powerstatistics for fault analysis (black box analysis), and provideappropriate alarms or corrective action based on the power readings.

In FIG. 1, the Pin (power input)=Vfeed*Ifeed. The maximum power inputrepresented by Pin(max) is equal to 100VA or 100 W. The voltage of theinput at the remote unit is represented by Vfeed wherein Vfeed=Vsource(voltage of the input source)−Vdrop (voltage drop over the cables whichis a function of the impedance (Z) of the cables). The maximum currentat the input is represented by Ifeed(max)=265 mA.

Pout (power output)=Vload*Iload wherein Vload is variable and between 39V to 75V as dictated by the DAC trim output from the digital powermanager.

The power efficiency of the system is computed through a simple equationstating that n (the power efficiency of system)=Pout/Pin.

In an alternative embodiment of the SEM, the various I2C devices alsotransmit information related to temperature status in addition tocurrent and voltage readings.

FIG. 2 depicts a method for providing end-to-end power efficiency in aremote unit (SEM). The method of providing end-to-end efficiency in aremote unit 20 involves an operation 21 for utilizing a first I2C deviceto monitor an input voltage and input current to the remote unit.Operation 22 involves providing the input voltage and input current to amain microprocessor for calculating an input power. Operation 23involves utilizing a second I2C device to monitor an output voltage andoutput current from the remote unit. Operation 24 involves providing theoutput voltage and the output current to the main microprocessor forcalculating an output power. Operation 25 involves calculating a powerefficiency of the remote unit at the main microprocessor based on theinput power and the output power. Operation 26 involves utilizing athird I2C device to provide the power efficiency of the remote unit to adigital power manager. Operation 27 involves utilizing the digital powermanager to control the DAC trim output to a DC/DC converter. The DACtrim output to the DC/DC converter allows various voltage outputs fromthe DC/DC converter to be tested to find the optimal one for creatingthe most power efficient remote unit given the current line and loadconditions.

Alternative embodiments of the method involve utilizing the first I2Cdevice to provide temperature measurements from the network feed monitorto the main microprocessor and utilizing the second I2C device toprovide temperature information from the BUS feed monitor and activeload to the main microprocessor.

FIG. 3 depicts an alternative method for providing end-to-end powerefficiency in a remote unit (SEM). This method of providing end-to-endefficiency in a remote unit 30 involves an operation 31 for utilizing afirst I2C device to monitor temperature at the input to the remote unit.Operation 32 involves providing the input temperature to a mainmicroprocessor. Operation 33 involves utilizing a second I2C device tomonitor the temperature at the output to the remote unit. Operation 34involves providing the output temperature to the main microprocessor.Operation 35 involves calculating a power efficiency of the remote unitat the main microprocessor. Operation 36 involves utilizing a third I2Cdevice to provide the power efficiency of the remote unit to a digitalpower manager. Operation 37 involves utilizing the digital power managerto control the DAC trim output to a DC/DC converter. The DAC trim outputto the DC/DC converter allows various voltage outputs from the DC/DCconverter to be tested to find the optimal one for creating the mostpower efficient remote unit given the current temperature conditions.

It is contemplated that the method described herein can be implementedas software, including a computer-readable medium having programinstructions executing on a computer, hardware, firmware, or acombination thereof. The method described herein also may be implementedin various combinations on hardware and/or software.

It will be recognized by those skilled in the art that changes ormodifications may be made to the above-described embodiments withoutdeparting from the broad inventive concepts of the invention. It shouldtherefore be understood that this invention is not limited to theparticular embodiments described herein, but is intended to include allchanges and modifications that are within the scope and spirit of theinvention as set forth in the claims.

The invention claimed is:
 1. A method for providing end-to-end powerefficiency in a device connected on a telecommunications loop comprisingthe steps of: (a) utilizing a first communication protocol device tomonitor an input voltage and input current to a remote unit; (b)providing the input voltage and the input current to a mainmicroprocessor for calculating an input power; (c) utilizing a secondcommunication protocol device to monitor an output voltage and outputcurrent from the remote unit; (d) providing the output voltage and theoutput current to the main microprocessor for calculating an outputpower; (e) calculating a power efficiency of the remote unit at the mainmicroprocessor based on the input power and the output power; (f)utilizing a third communication protocol device to provide the powerefficiency of the remote unit to a digital power manager; and (g)utilizing the digital power manager to control the DAC trim output to aDC/DC converter.
 2. The method of claim 1 further comprising the stepsof: (a) utilizing the first communication protocol device to detect achange in the input voltage or the input current to the remote unit; (b)utilizing the second communication protocol device to detect a change inthe output voltage or the output current from the remote unit; (c)notifying the main microprocessor of any change in the input voltage,the input current, the output voltage or the output current; and (d)utilizing the main microprocessor to notify the digital power manager ofany change in the input voltage, the input current, the output voltageor the output current.
 3. The method of claim 1 wherein the firstcommunication protocol device, the second communication protocol deviceand the third communication protocol device are I2C devices.
 4. Themethod of claim 3 wherein the I2C devices use optoisolation.
 5. Themethod of claim 1 wherein the remote unit is a sealed expansion modulelocated remotely from an input power source.
 6. The method of claim 1wherein the DAC trim output to the DC/DC converter allows variousvoltage outputs from the DC/DC converter to be tested to find an optimalone for creating the most power efficient remote unit given the currentline and load conditions.
 7. A method for providing end-to-end powerefficiency in a device connected on a telecommunications loop comprisingthe steps of: (a) utilizing a first communication protocol device tomonitor an input temperature to a remote unit; (b) providing the inputtemperature to a main microprocessor; (c) utilizing a secondcommunication protocol device to monitor an output temperature from theremote unit; (d) providing the output temperature to the mainmicroprocessor; (e) calculating a power efficiency of the remote unit atthe main microprocessor at the input temperature and the outputtemperature; (f) utilizing a third communication protocol device toprovide the power efficiency of the remote unit to a digital powermanager at the input temperature and the output temperature; and (g)utilizing the digital power manager to control the DAC trim output to aDC/DC converter.
 8. The method of claim 7 further comprising the stepsof: (a) utilizing the first communication protocol device to detect achange in temperature at an input to the remote unit; (b) utilizing thesecond communication protocol device to detect a change in temperatureat an output from the remote unit; (c) notifying the main microprocessorof any change in temperature at the input of the remote unit or theoutput of the remote unit; and (d) utilizing the main microprocessor tonotify the digital power manager of any change in temperature at theinput of the remote unit or the output of the remote unit.
 9. The methodof claim 7 wherein the first communication protocol device, the secondcommunication protocol device and the third communication protocoldevice are I2C devices.
 10. The method of claim 9 wherein the I2Cdevices use optoisolation.
 11. The method of claim 7 wherein the remoteunit is a sealed expansion module located remotely from an input powersource.
 12. The method of claim 7 wherein the DAC trim output to theDC/DC converter allows various voltage outputs from the DC/DC converterto be tested to find an optimal one for creating the most powerefficient remote unit given the current line and load conditions.
 13. Amethod for providing end-to-end power efficiency in a device connectedon a telecommunications loop comprising the steps of: (a) monitoring aninput power and an output power in the device; (b) calculating a powerefficiency of the device based on the input power and the output power;and (c) adjusting voltage within the device to improve the powerefficiency of the device by controlling a DAC trim output to a DC/DCconverter of the device.
 14. The method of claim 13 wherein the deviceis a sealed expansion module located remotely from an input powersource.